A vehicle can include an internal combustion engine coupled to a transmission and a final drive to rotate wheels that move the vehicle. To start the engine of a non-hybrid vehicle, a starter motor can be energized which causes a crankshaft of the engine to turn and start the engine.
A hybrid electric vehicle utilizes both an electric motor-generator and an internal combustion engine to offer reduced fuel consumption and emissions. One type of hybrid electric vehicle utilizes a belted-alternator-starter (BAS). The BAS utilizes a motor-generator coupled to a crankshaft of the engine usually by a belt and pulley system. The motor-generator can restart the engine when a brake is released at a stop light and the motor-generator can be rotated by the engine during regenerative braking. This type of hybrid vehicle utilizes a starter motor independent of the motor-generator to start the engine when the engine has been shut off for an extended period of time. The starter motor and the motor-generator operate separately, i.e., not coupleable to each other.
The BAS can be in electrical communication with at least a first energy storage device. The vehicle can have an electrical system that runs various vehicle accessories such as headlights, HVAC devices, auxiliary motors and entertainment system components. Any current exiting the BAS is fed to the first energy storage device before the current can reach the electrical system, and thus, the electrical system is not powered directly by the BAS.